Fellow Pilots,

I’d rather not go into details (will do later on) but I lost my Mavic but seem to know where it is.

As I have one day of my holiday remaining and because of my care-agreement with DJI all is aimed at retrieving the crashed aircraft.

  

As you can see on the logfiles (not sure how to get those to you) I have ditched my Mavic in a small lake at a holiday park in beautiful Slovenia. It went down straight vertically so I should be able to retrieve it. Unfortunately the water is about 3-4 meters deep with no visibility. The bottom of the lake is mostly sand but almost no vegetation or weed. So I should be able to find it – with some luck. The only issue is – I am on holiday and do not have any tools, ropes, or stuff like that. I did purchase a nifty inflatable boat

Not sure if my complete text came through.... Just to be sure - this was the complete message:

TheoR. Posted at 2017-8-11 19:37
Not sure if my complete text came through.... Just to be sure - this was the complete message:

Fellow Pilots,

  

I’d rather not go into details (will do later on) but I lost my Mavic but seem to know where it is. As I have one day of my holiday remaining and because of my care-agreement with DJI all is aimed at retrieving the crashed aircraft.

  

As you can see on the logfiles (not sure how to get those to you) I have ditched my Mavic in a small lake at a holiday park in beautiful Slovenia. It went down straight vertically so I should be able to retrieve it. Unfortunately the water is about 3-4 meters deep with no visibility. The bottom of the lake is mostly sand but almost no vegetation or weed. So I should be able to find it – with some luck. The only issue is – I am on holiday and do not have any tools, ropes, or stuff like that. I did purchase a nifty inflatable boat

  

The most important thing however – how accurate is the log? This determines the area I need to swim and cover. If it is just about 5 meters it should be possible.. But around 10 or more?

  

Maybe the is someone from Slovenia who is reading this forum? Who can advise me with the language, names of tools but also location of nearby (sport)fishing shops. I am in the vicinity of Terme Catez.

  

Hope someone can help, willing to pay for it… A lot of you might suggest ‘”Google is your best friend but with a 0,001kbs connection most of the webpages do not open….

  

Theo.  

  

TheoR. Posted at 2017-8-11 19:41
Fellow Pilots,  I’d rather not go into details (will do later on) but I lost my Mavic but seem to know where it is. As I have one day of my holiday remaining and because of my care-agreement with DJI all is aimed at retrieving the crashed aircraft.   As you can see on the logfiles (not sure how to get those to you) I have ditched my Mavic in a small lake at a holiday park in beautiful Slovenia. It went down straight vertically so I should be able to retrieve it. Unfortunately the water is about 3-4 meters deep with no visibility. The bottom of the lake is mostly sand but almost no vegetation or weed. So I should be able to find it – with some luck. The only issue is – I am on holiday and do not have any tools, ropes, or stuff like that. I did purchase a nifty inflatable boat  The most important thing however – how accurate is the log? This determines the area I need to swim and cover. If it is just about 5 meters it should be possible.. But around 10 or more?  Maybe the is someone from Slovenia who is reading this forum? Who can advise me with the language, names of tools but also location of nearby (sport)fishing shops. I am in the vicinity of Terme Catez.  Hope someone can help, willing to pay for it… A lot of you might suggest ‘”Google is your best friend but with a 0,001kbs connection most of the webpages do not open….  Theo.

DroneFlying will probably happen upon this. He can give you instructions retrieving your logs.

Are you on iOS or Android?

It's a pity to hear such an accident. The final GPS signal only records the last point when the flight record interrupted. Whether the drone will stay here or not can not be ensured. If the drone unfortunately can not be found, I would recommend you to send an email to our Support Team via support.eu@dji.com to report the accident.

TheoR. Posted at 2017-8-11 19:41
Fellow Pilots,  I’d rather not go into details (will do later on) but I lost my Mavic but seem to know where it is. As I have one day of my holiday remaining and because of my care-agreement with DJI all is aimed at retrieving the crashed aircraft.   As you can see on the logfiles (not sure how to get those to you) I have ditched my Mavic in a small lake at a holiday park in beautiful Slovenia. It went down straight vertically so I should be able to retrieve it. Unfortunately the water is about 3-4 meters deep with no visibility. The bottom of the lake is mostly sand but almost no vegetation or weed. So I should be able to find it – with some luck. The only issue is – I am on holiday and do not have any tools, ropes, or stuff like that. I did purchase a nifty inflatable boat  The most important thing however – how accurate is the log? This determines the area I need to swim and cover. If it is just about 5 meters it should be possible.. But around 10 or more?  Maybe the is someone from Slovenia who is reading this forum? Who can advise me with the language, names of tools but also location of nearby (sport)fishing shops. I am in the vicinity of Terme Catez.  Hope someone can help, willing to pay for it… A lot of you might suggest ‘”Google is your best friend but with a 0,001kbs connection most of the webpages do not open….  Theo.

As you can see on the logfiles (not sure how to get those to you)

The log file that may be helpful will be the TXT file stored on your mobile device for the last flight. The instructions on how to retrieve it are here and once you've retrieved it you should upload it to PhantomHelp and then provide a link in this thread to the uploaded log data. Good luck.

TheoR. Posted at 2017-8-11 19:41
Fellow Pilots,  I’d rather not go into details (will do later on) but I lost my Mavic but seem to know where it is. As I have one day of my holiday remaining and because of my care-agreement with DJI all is aimed at retrieving the crashed aircraft.   As you can see on the logfiles (not sure how to get those to you) I have ditched my Mavic in a small lake at a holiday park in beautiful Slovenia. It went down straight vertically so I should be able to retrieve it. Unfortunately the water is about 3-4 meters deep with no visibility. The bottom of the lake is mostly sand but almost no vegetation or weed. So I should be able to find it – with some luck. The only issue is – I am on holiday and do not have any tools, ropes, or stuff like that. I did purchase a nifty inflatable boat  The most important thing however – how accurate is the log? This determines the area I need to swim and cover. If it is just about 5 meters it should be possible.. But around 10 or more?  Maybe the is someone from Slovenia who is reading this forum? Who can advise me with the language, names of tools but also location of nearby (sport)fishing shops. I am in the vicinity of Terme Catez.  Hope someone can help, willing to pay for it… A lot of you might suggest ‘”Google is your best friend but with a 0,001kbs connection most of the webpages do not open….  Theo.

Snorkel goggles swim 5 metres is not to deep.

ephektz Posted at 2017-8-11 19:59
DroneFlying will probably happen upon this. He can give you instructions retrieving your logs.

Are you on iOS or Android?

Hi,

This is the link to the Flightlog. It was a Litchi flight.

http://www.phantomhelp.com/LogViewer/NC69J6EVIOZZIVYL3LND/

Thanks for reaching out...

TheoR. Posted at 2017-8-16 03:50
Hi,

This is the link to the Flightlog. It was a Litchi flight.

This might also be useful - contains even more information.

http://app.airdata.com/main?share=GNBgqc

I know this wont help and I am really sorry for your loss.............but I am dying to know the back story to this seeing as there does not look to have been a failure with the AC

Good luck!

J

Jinjur Posted at 2017-8-16 04:16
I know this wont help and I am really sorry for your loss.............but I am dying to know the back story to this seeing as there does not look to have been a failure with the AC

Good luck!

J,

Indeed - if this was a human error or a mechanical failure I would be something to learn from or to improve. I have been flying drones for 5 years and I never had to deal with this kind of problem: 2,2 seconds of signal loss, controller disconnects, uncontrollable ascend, return to home kick's in and aircraft is forced to land...

If the Mavic passes 200 meters it's almost impossible to keep on hearing it's engines. It was a very, bright sunny day so visual beyond 200 meters was also not possible, even with my sunshades. People who were camping around the pond did not hear or see anything as well.

I still hope to retrieve the aircraft but I doubt if it will tell us something. It has been a full week now and the unit is still lying on the bottom of 4m water...

Have had no further reactions on my logs so it's noting common either.

Appreciate your reaction.

TheoR. Posted at 2017-8-16 03:50
Hi,

This is the link to the Flightlog. It was a Litchi flight.

The last reported location was 45.889255, 15.628519, so that's where you'll want to look. Start as close as you can to those coordinates and then swing in a circle with a gradually increasing radius for best results. Good luck.

TheoR. Posted at 2017-8-17 00:44
J,

Indeed - if this was a human error or a mechanical failure I would be something to learn from or to improve. I have been flying drones for 5 years and I never had to deal with this kind of problem: 2,2 seconds of signal loss, controller disconnects, uncontrollable ascend, return to home kick's in and aircraft is forced to land...

It has been a full week now and the unit is still lying on the bottom of 4m water...  Have had no further reactions on my logs so it's noting common either.

You posted the logs less than 24 hours ago after being asked to provide them four days earlier; if you'd like a quicker turnaround on replies then you'll need to be a little more timely in providing the requested information.

DroneFlying Posted at 2017-8-17 04:47
It has been a full week now and the unit is still lying on the bottom of 4m water...  Have had no further reactions on my logs so it's noting common either.

You posted the logs less than 24 hours ago after being asked to provide them four days earlier; if you'd like a quicker turnaround on replies then you'll need to be a little more timely in providing the requested information.

Droneflyer,

My sincere apologies... I totally agree, need to be more patient and wait for the results.
It really keeps me up at night. Not only the financial loss, but also my reputation.

You might not know this but I am promoting safe drone flight and created a free App for our community:
https://www.drone-copilot.com/

Really can't stand the idea to have done something wrong...

Again, my apologies,

Theo.

TheoR. Posted at 2017-8-17 06:40
Droneflyer,

My sincere apologies... I totally agree, need to be more patient and wait for the results.

No problem.

Really can't stand the idea to have done something wrong

I'm not convinced that you did anything wrong, but in any case we all make mistakes so you shouldn't beat yourself up over it too much. The data suggests that your Mavic started landing even though it was pretty high up but unfortunately the information I'd really like to see isn't included in PhantomHelp's representation of this log since it came from Litchi. Ideally I'd like to take a look at the DAT file, but of course you'd have to recover the aircraft first and even then it's not clear you'd be able to extract the log.

I'm guessing you already know that DJI isn't likely to offer a warranty replacement without the aircraft or a log from the Go app, so even if it was a product defect you're going to need to recover the aircraft to have much hope of getting a warranty replacement. I do hope you're able to recover the Mavic; good luck.

Just looked at the parameters on airdata and only one thing stands out to me. Under the notifications tab reference line H (mode changed to confirm landing) at 391 meters. After looking at various flights i've done that message doesn't appear until the mavic has stopped short of the ground and cleared itself to land. The aircraft was descending at 15 M/s which is far from terminal velocity but it was a healthy descent. When I was traveling I was able to conduct some flights where I was able to max the aircraft out because I like knowing the limitations and capability of things I fly. A similar flight profile had mine descending at half the rate yours was in similar conditions and winds aloft. Quite honestly I think something malfunctioned causing the mavic to enter its final landing stage before it should have. Oh and it's probably exactly where it shows on the map, might want to get some goggles and go for a dip.

For reference I calculated terminal velocity with the following: Aircraft Weight: 739g, CS area of 10sq inches, Drag Coefficient of .5 (its pretty sleek I guess), Air Density of 1.5, and at 1G = 54.7 M/s
I also converted inches to meters.

Hi Theo - victormike below is correct - mavic descent spec is 5m/s - dropping at 15m/s is a problem. good luck - sorry for yr loss and frustration

15 meters per second is 33MPH or 54KPH   unless something is mixed up and logging wrong, that decent speed is way too fast

ImHereToCrash Posted at 2017-8-17 11:18
15 meters per second is 33MPH or 54KPH   unless something is mixed up and logging wrong, that decent speed is way too fast

OK, thanks guys, very useful information...

Do you have any idea what might have happened to the drone when it hit the water at 15 meter per second? In other words, will it still be in one piece?

This might explain why I was unable to dive and find it myself.

It will also help the diver look for debris instead of a complete Mavic.

Thanks again,

Theo.

it will likely still be in 1 peice, 33MPH impact would not tear apart the body of the drone..    as for  if it would have moved once hit the water? maybe alot of energy and it could have sunk a few meters in any direction..

my theory behind what happened.. landing protection should have stopped it from landing on the surface of the water... hovered above it a bit...  your battery was at 74%.   it would have tried to return home on RC signal loss (by default)  or tried to RTH on low battery (by default)..   my guess is its not in the lake unless you watched it sink under...... and that it is instead somewhere else..maybe someone grabbed it and took it...or maybe it tried to return home... did you check the home point? and surrounding areas?

The thing is pretty tough. I would expect it to be intact unless you had the gimbal cover off- If it was, expect the camera to be detached probably, broken props are likely. I would expect it to be very very close to that last location.

VictorMike Posted at 2017-8-17 07:28
Just looked at the parameters on airdata and only one thing stands out to me. Under the notifications tab reference line H (mode changed to confirm landing) at 391 meters. After looking at various flights i've done that message doesn't appear until the mavic has stopped short of the ground and cleared itself to land. The aircraft was descending at 15 M/s which is far from terminal velocity but it was a healthy descent. When I was traveling I was able to conduct some flights where I was able to max the aircraft out because I like knowing the limitations and capability of things I fly. A similar flight profile had mine descending at half the rate yours was in similar conditions and winds aloft. Quite honestly I think something malfunctioned causing the mavic to enter its final landing stage before it should have. Oh and it's probably exactly where it shows on the map, might want to get some goggles and go for a dip.

For reference I calculated terminal velocity with the following: Aircraft Weight: 739g, CS area of 10sq inches, Drag Coefficient of .5 (its pretty sleek I guess), Air Density of 1.5, and at 1G = 54.7 M/s

I suggest going to any dive shop, and giving the exact location to the shop.  Ask for any member to retrieve it for you for say $100 and mail it to you at your cost.  I'd do it in a heartbeat (for free) if I were a local diver...good luck.  If you have already left you can look up local dive shops online in that area and ask for their help.

randy.sauder Posted at 2017-8-17 18:27
I suggest going to any dive shop, and giving the exact location to the shop.  Ask for any member to retrieve it for you for say $100 and mail it to you at your cost.  I'd do it in a heartbeat (for free) if I were a local diver...good luck.  If you have already left you can look up local dive shops online in that area and ask for their help.

Thanks again for all your help...

Luckily, I am still in contact with someone from the Slovenian DJI community who on his turn is trying to arrange some local divers. I hoped that the 200$ "reward" would trigger them but up to now we are struggling to find a diver. The incident happened about 2000km from my home so that does not make it easier.

We have searched the area, and it's a highly populated camping site. We also have reported the incident at the reception and asked many people who were close by at the incident. So it's not a remote area or something.

In the meantime DJI responded that "A Special Team will contact you via email as soon as the results have been readily available to discuss the details of the incident and the possible option."

Just have to be patient I guess...

Theo.

Hi guys,

Today I have finally received an answer from DJI. My Fly Away incident was on the 10th of August.
This is their reply:

"We regret to inform you due to the fact that you were using a non DJI app that we are unable to confirm your flight records as we do not have the resources to analyze data from other app as such we unfortunately cannot provide further assistance with this issue(http://www.dji.com/service/policy) because the flight records are essential to the analysis process the only other way to recover the flight records is if you recovered the drone. We apologize for this unfortunate turn of events and hope for your understanding with this matter."

The drone is still missing but all of the existing logfiles indicate that there was something wrong. Strange enough: "We do not have the resources" instead of "It's not our policy". The logfiles from UAV are synced on both the  GO-App and the Litch app so they do not have to have more "resources"?
I will try the Litchi forum but it's not acceptable. Why else would you create an SDK for? Litchi is being used by thousands on Phantoms and Mavics.

Will keep you posted.

Guys,

Another similar issue reported on the Litchi forum:

"There is obviously something wrong with the Mavic. At 7:10, altitude is 1187", at 7:10.2 it is -28". Even free fall is not as fast. Looks like a barometer failure, exactly what happened to me with my first Mavic during its third flight. This AC was exchanged under warranty but as I said, the failure did not result in the lost of the Mavic that I could land (just before landing at home point, altitude display and recording was about -300". Just after landing, it returned to the expected zero feet).".

The log files do not lie nor did I alter them. What more could DJI want?

Besides the obvious and by now fully destroyed Mavic.

Thanks.

Answer from DJI support yesterday:

Thank you for contacting DJI Technical Support. We totally understand that you have questions that needs to have an answer and we will try to answer those questions as much as we can.

With regards on using and running the Litchi app and SDK on the mavic are considered as "third party applications/softwares and equipment. Thus they are not being physically used, these programs and applications are being considered as products because customers such as yourself is using and downloading it.Therefore, using these applications and softwares will going to void the warranty of the drone and DJI has liability whatsoever if there will be an accident that might happened on the drone

(Please see image below):  

They say that the warranty is void if the crash is caused by 3rd party / Litchi. But is really the barometer from the Mavic.
Beings me to the following question - where exactly is the barometer in the aircraft? A few months ago I have a crash in to a tree and they repaired portions around the gimbal. Maybe this could point to the caiuse...

Thanks again!

Sorry for all the questions... Before the FlyAway on the 10th I flew more or less the same route on the 8th of August.
This went quite well. Maybe someone can see abnormalities here?

Here is the link:

http://app.airdata.com/main?share=XbNAfD

TheoR. Posted at 2017-9-16 02:06
Answer from DJI support yesterday:

Thank you for contacting DJI Technical Support. We totally understand that you have questions that needs to have an answer and we will try to answer those questions as much as we can.

I'm sorry to hear about DJI's response but not surprised; I agree that Litchi doesn't appear to be the cause of this loss, but as I mentioned before it's difficult to prove anything either way without a log DJI will / can examine.

As far as the barometer goes, it's a chip inside the Mavic, though I doubt your problem was caused by a faulty barometer. It's much more likely that it was caused by faulty VPS readings that made the FC think it was close to the ground and should start landing. I've seen a few other people who had this problem occur and got warranty replacements, but an important difference is that they all had logs from the Go app that showed the sequence of events.

Guys,

I have asked advice from the Litchi forum and below their conclusion. However DJI keeps on refusing to have a look at my log files and every answer is "we do not support 3rd party and if the problem is caused by 3 rd party App then your warranty is void". The evidence of the failure is just one click away:  http://app.airdata.com/main?share=GNBgqc. DJI does not have any evidence that Litchi caused the issue. They just keep on pointing to their after sale policies and refuse to take a look at AirData (which also supports DJI-GO by the way).

You might think "What is this guy moaning about, just take your $1000,- loss and continue with the nice things in life..."

However for me this is becoming an principle matter and everyone using //litchi needs to be aware of this situation. My bad luck is that it crashed in a lake and I still hope that it will be found but my confidence in DJI support is completely gone.

As they have no evidence and I do (log files) - would it make sense to go to court for this? Or maybe there are (European) rules for these things? I will not give up.

"Apparently, in C you just lost the downlink for 2 1/2 seconds, but not the connection between the RC and the AC.
From C (3:35) to D (5:56), your drone remains in Waypoint mode. This means that it continues to fly autonomously according to the programmed mission. With Litchi, once the mission is uploaded and started, there is no need of the app or even of the RC. You can shut off your device and your RC, the drone will fly to the last waypoint by itself at the speed and with the gimbal tilt that were programmed at the moment of disconnection.

Thus if this last waypoint is programmed close to the place you are and the programmed speed is fast enough, you have just to wait quietly for your bird.
But since you were still in waypoint mode during these 2 minutes 20 seconds between C and D, I am surprised that the speed remained at very low values (varying randomly between 0.2 and 4mph but mostly around 1mph) as it was before the downlink loss in C.

To me, this is reminiscent of a drift (with some accelerations under gusts) when the drone is hovering for a long period with some wind. The programmed speed was quite above zero.
What is even more strange is the slow but regular ascension from 204 feet to 1,168 feet during these 2' 20s.

Together with the abnormally low altitude value (-336 feet) at the moment the drone lands in the lake under P-GPS and 19 satellites (!), this raises the possibility of a barometer and/or sensor failure allowing a great discrepancy with the GPS data (a ~100m error is huge with 19 satellites).

This is the non-disputable point that I would put forward to contest the decision of DJI because this error cannot be explained by any pilot error or erroneous command of Litchi app."